Soil Survey of Sweet Grass County Area, Montana - Soil Data Mart

38 Soil Survey
Clay content: 40 to 50 percent
Content of rock fragments: 0 to 15 percent gravel
Electrical conductivity: 8 to 16 mmhos/cm
Sodium adsorption ratio: 4 to 13
Reaction: pH 6.6 to 7.8
Bzg horizons
Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Redox concentrations: Few to many; chroma of 6
Texture (less than 2 mm): Clay or clay loam
Clay content: 35 to 60 percent
Content of rock fragments: 0 to 15 percent gravel
Electrical conductivity: 8 to 30 mmhos/cm
Sodium adsorption ratio: 4 to 13
Reaction: pH 7.4 to 8.4
Bkzg horizons
Hue: 2.5Y or 5Y
Value: 5 or 6 dry; 4 or 5 moist
Chroma: 1 or 2
Redox concentrations: Few to many; chroma of 6
Texture (less than 2 mm): Clay or clay loam
Clay content: 35 to 60 percent
Content of rock fragments: 0 to 25 percent gravel
Electrical conductivity: 4 to 16 mmhos/cm
Sodium adsorption ratio: 4 to 13
Calcium carbonate equivalent: 5 to 15 percent
Reaction: pH 7.9 to 9.0
Birney Series
Depth class: Very deep (greater than 60 inches)
Drainage class: Well drained
Permeability: Moderate (0.6 to 2.0 inches/hour)
Landform: Escarpment
Parent material: Gravelly colluvium
Slope range: 15 to 60 percent
Elevation range: 3,750 to 5,200 feet
Mean annual precipitation: 10 to 14 inches
Mean annual air temperature: 43 to 46 degrees F
Frost-free period: 95 to 125 days
Taxonomic Class: Loamy-skeletal, mixed,
superactive, frigid Aridic Haplustepts
Typical Pedon
Birney channery loam, in area of Birney-Yawdim-
Rock outcrop association, steep, 300 feet south and
500 feet west of the northeast corner of the southeast
quarter of sec. 25, T. 2 S., R. 21 E.; Stillwater County,
Montana.
A—0 to 4 inches; brown (10YR 5/3) channery loam,
dark brown (10YR 4/3) moist; weak medium
granular structure; soft, very friable, slightly
sticky, slightly plastic; many very fine and fine
roots; 20 percent hard shale and sandstone
channers; slightly effervescent; moderately
alkaline (pH 7.9), clear smooth boundary.
Bw—4 to 14 inches; yellowish brown (10YR 5/4) very
channery loam, dark brown (10YR 4/3) moist;
weak medium prismatic structure parting to
moderate fine subangular blocky; soft, very
friable, slightly sticky, slightly plastic; many
very fine roots; common very fine tubular pores;
40 percent hard shale and sandstone channers;
slightly effervescent; moderately alkaline
(pH 8.4); clear smooth boundary.
Bk1—14 to 24 inches; pale brown (10YR 6/3) very
channery sandy loam, yellowish brown (10YR
5/4) moist; massive; soft, very friable, slightly
sticky, nonplastic; common very fine and fine
roots matted around rock fragments; common or
many carbonate coats on undersides of rock
fragments; 50 percent hard shale and sandstone
channers; violently effervescent; moderately
alkaline (pH 8.4); gradual wavy boundary.
Bk2—24 to 60 inches; pale brown (10YR 6/3) very
channery sandy loam, brown (10YR 5/3) moist;
massive; soft, very friable, slightly sticky,
nonplastic; few fine roots; common or many
carbonate coats on undersides of rock fragments;
60 percent hard shale and sandstone channers;
moderately effervescent; moderately alkaline
(pH 8.4).
Range in Characteristics
Soil temperature: 42 to 47 degrees F
Moisture control section: Between 8 and 24 inches
Depth to the Bk horizon: 10 to 15 inches
Note: Some pedons have a C horizon.
A horizon
Hue: 10YR
Value: 4 to 6 dry; 3 or 4 moist
Chroma: 2 to 4
Texture (less than 2 mm): Loam
Clay content: 10 to 25 percent
Content of rock fragments: 0 to 35 percent
channers
Calcium carbonate equivalent: 1 to 10 percent
Reaction: pH 7.4 to 8.4
Bw horizon
Hue: 10YR
Value: 4 to 6 dry; 4 or 5 moist